A flat-panel detector digital radiography and a storage phosphor computed radiography: screening for pneumoconioses.

Storage phosphor computed radiography (SR) and flat-panel detector (FPD) radiography are two types of digital X-ray utilizing different techniques. We compared these two techniques with conventional analogue chest radiograph (AR) among pneumoconiotic patients and healthy controls. Thirty individuals consisting of 20 silica-exposed ex-workers and 10 healthy controls without occupational exposure to any mineral dust were examined with chest X-ray by AR, SR and FPD. Three occupational physicians, including one NIOSH B reader, assessed the digital and conventional radiographs by the side-by-side method according to the ILO 2000 International Classification of Radiograph of Pneumoconioses (ILO/ICRP). No significant difference was shown between the subjective film qualities by AR and FPD. Inter-reader agreement of the profusion of small opacities on radiographs was high in the order of SR (kappa=0.64), FPD (kappa=0.62), and AR (kappa=0.55). The profusions of small opacity for AR and FPD by the 12-point scaled profusion of ILO/ICRP did not show a statistically significant difference, but those for AR and SR showed a significant difference. The areas under the receiver operator curves (ROC) using clinical diagnosis by a pulmonologist as the reference showed no statistically significant difference among the three radiographic techniques. FPD gives image quality as good as that of AR, and it has acceptable agreement with AR in small profusion categories, which consequently assures its application to pneumoconiosis screening. SR showed less profusion than FPD and AR, which can be fixed with image modification.